Female macroptera. Body yellow, compound eyes with 4 ommatidia weakly to deeply shaded; tergites II–VIII brown medially, ocellar triangle and anterior half of mesonotum sometimes brown; antecostal ridges on tergites III–VIII dark medially but paler laterally; sternal antecostal ridges on III–VII dark; fore wings uniformly weakly shaded; antennal segment 1 pale, II variable, III–IV pale with apex shaded, V–VIII dark. Head with vertex closely striate, ocellar triangle with transverse lines; bases of ocellar setae pair III usually separated by at least the length of these setae, arising well anterior of tangent to anterior margins of posterior ocelli toward margins of ocellar triangle; three pairs of post-ocular setae at least as long as ocellar setae pair III; mouth cone long, extending to mesosternum. Pronotum with closely spaced anastomosing transverse striae; posteromarginal setae S2 about twice the length of S1, S1 subequal to S3 and both longer than S4 and S5. Metanotal sculpture transversely reticulate anteriorly and longitudinally reticulate posteriorly; median setae close to margin. Fore wing scale with 4–5 marginal setae; first vein setae 3–14+1–9+1–2+0–1+0–1; second vein 4–6 setae; proximal posteromarginal fringe cilia straight. Bases of median tergal setae on segments III–V almost in-line with tergal discal setae, separated by no more than 0.75 times the length of these setae; tergal microtrichial fields with 3 discal setae; VIII with a few discal microtrichia anteromedially, posteromarginal comb interrupted medially; tergite IX with microtrichia on posterior half. Sternites with microtrichia reduced, scarcely extending mesad of setae S3.
Male macroptera. Similar in colour and sculpture to female, but smaller; abdominal segment IX without paired drepanae; aedeagus without paired array of spines laterally, but with group of small spines at apex.
The genus Scirtothrips comprises over 100 described species worldwide, with 21 species known from Australia most of which are endemics to this continent. These species all have the lateral thirds of the abdominal tergites covered in closely spaced rows of fine microtrichia, and in many species the sternites also bear similar microtrichia. The antennae are 8-segmented, except in S. casuarinae and S. solus, both forewing veins have an irregular and incomplete setal row, and a median spinula is present on both the meso and metafurca. S. pilbara is variable, and probably represents a widespread species-group across Australia that is associated with Acacia foliage, and in which the mouth cone usually extends to the mesosternum.
Known only from Australia.
Western Australia, Northern Territory, Queensland.
Presumably feeding and breeding on young phyllodes.
Various Acacia spp (Mimosaceae)
Scirtothrips pilbara Hoddle & Mound
Hoddle MS & Mound LA. 2003. The genus Scirtothrips in Australia (Insecta, Thysanoptera, Thripidae). Zootaxa 268: 1-40. http://www.mapress.com/zootaxa/2003f/zt00268.pdf